Most big firms have a concern line/department you can report to in case of ethics or internal policy compliance issues, check, but maybe they won't even reveal

Most big firms have a concern line/department you can report to in case of ethics or internal policy compliance issues, check, but maybe they won't even reveal your identity. If there is no such a line, I would start looking for another job if the felony is not a serious one, otherwise I would ask advice to a lawer. You seem to be somewhat junior? It seems to me you don't have enough experience to navigate the political landscape of your firm and a wrong move there might really hurt your carrier, so probably changing job is the best long term strategy here.